1. Field of the Invention
The present invention relates to a touch-control structure. More particularly, the present invention relates to a touch-control structure for use in a flexible display device.
2. Descriptions of the Related Art
With the advancement of science and technology, display devices have become thinner and more lightweight to reduce the occupying space and weight. In the mean time, with the development of the user interface, the touch panel has become a very common input interface. However, as the display device becomes thinner, the thin profile provides relatively insufficient structural strength. In addition, the substrate of the conventional thin-profile display device, such as a liquid crystal display device, mainly consists of glass, which can be easily deformed with external forces and damaged accordingly.
To overcome the shortcoming of the conventional display devices, the development of flexible display devices has drawn much attention. The most common available flexible display technologies, such as electronic paper utilizing the electronic ink (E-ink) or organic light emitting diode display technologies utilizing the organic semiconductor, have realized the thin-profiled flexible display device to a certain extent. However, it is still difficult to apply a touch-control function to an existing flexible display device with these products.
The touch-control method that has been used in conventional display devices, such as resistive or capacitive touch-control technologies, has mainly been applied to hard substrates, such as a glass substrate. During the manufacturing process of forming the transparent conductive film on the substrate, the substrate has to be heated to a high processing temperature, so that the transparent conductive film can tightly adhere to the substrate. However, the excessive heat energy of this high temperature will damage the flexible substrate, which commonly utilizes organic plastic material, and further damage the touch-control function. On the contrary, forming the transparent conductive film with a relatively low processing temperature tends to degrade the conducting property and transparency of the transparent conductive film. Furthermore, it would be difficult for the transparent conductive film to adhere onto the substrate when formed with low temperature and would further cause the film to peel. As a result, it would be difficult to form the transparent conductive film of good quality on the flexible substrate, which in turn makes it difficult to raise the yield rate of the product utilizing the flexible substrate.
Furthermore, the touch-control film is disposed on the front side of the visible surface of a display device in the conventional touch-control display technologies. This arrangement will have the image brightness reduced due to the absorption by the touch-control film. In the touch-control display device with self-illumination, the brightness can be maintained by simply increasing the brightness of the light source. However, it would be difficult to overcome the problem when applying the touch-control film of the conventional arrangement to non-self-illuminating display technologies which utilize environmental light sources, such as electronic paper utilizing electronic-ink.
In view of this, it is important to provide a touch-control structure for a flexible display device which can maintain the brightness of the image.